STM software aids smart-building controls

  • October 5, 2020
  • Steve Rogerson

Swiss electronics company ST Microelectronics has released KNX software for its S2-LP low-power radio transceiver to enable energy-saving standard wireless connectivity for smart-building controls.

Ready to run on an STM32 microcontroller (MCU) or alternatively on a Blue NRG-2 Bluetooth Low Energy system-on-chip (SoC) that embeds an Arm Cortex-M0 core running at 32MHz and a set of IO peripherals, the software contains a certified KNX-RF stack, RF adaptation layer, and S2-LP library to connect the transceiver to create an ultra-low-power wireless KNX node.

Operating in the 868.3MHz band at 10mA with +10dBm output, the S2-LP delivers energy efficient, secure and robust wireless connectivity prolonging battery run-time and reducing the overall cost.

Combining the S2-LP radio and Blue NRG-2 SoC enables a hybrid and low-power optimised KNX-Bluetooth option in two chips, allowing a smartphone to access KNX-based networks and provide an intuitive and stylish interface for conveniently monitoring, controlling, configuring, provisioning and updating the KNX nodes.

Whether hosted on the Blue NRG-2 or STM32 MCU, the software enables innovation and power savings for pushbuttons, light switches, occupancy sensors, roller-shutter controls, dimmer actuators and other devices for lighting, heating, HVAC and energy-harvesting systems.

The software meets the latest KNX-RF Multi specification, which supports secure (S mode), encrypted communications and frequency agility with five channels to help avoid interference and permit fast and slow communication modes to save power. Further features boost reliability and allow larger numbers of KNX devices to coexist on the network, including listen before talk (LBT), fast acknowledge with auto-retry, and support for repeaters.

To create the KNX-RF Multi software, STM teamed with its authorised partners Tapko for the certified KNX stack and Actimage for the RF adaptation layer.

The S2-LP package joins STM’s STKNX integrated transceiver for KNX TP communication over twisted-pair cable and extends the company’s portfolio of certified products for smart-building communication, which covers the major industry standards. In addition to enabling both wired and wireless KNX specifications, STM provides embedded software, evaluation tools and mobile apps to accelerate the development of Bluetooth Low Energy Mesh and 6LoWPan networking for smart-building and industrial applications.

Both S2-LP and Blue NRG-2 devices belong to the STM ten-year longevity programme.

STM collaborated with electronics distributor Mouser Electronics to produce an ebook that explores strategies for overcoming challenges facing designers of smart home devices. In “7 Experts on Designing Commercially Successful Smart Home Devices”, subject matter experts from companies such as Microsoft, Cisco and Ingersoll Rand offer their perspectives on the most important factors for developing IoT products.

Homes and commercial buildings have evolved to incorporate intelligent design across a wide range of applications, with smart devices controlling everything from lighting and climate to HVAC and security. These interconnected systems require carefully planned design engineering as well as detailed knowledge into the specific needs for a successful connected device. Smart buildings and cities bring together a network of sensors, processors, artificial intelligence and connectivity, challenging engineers to maintain mastery of an extensive range of technologies and products.

The ebook offers plenty of food for thought for developers and engineers, covering topics such as edge processing, user experience and life cycle design. It also includes information on several STM products, including the STM32 L5 low-power microcontroller.